V Class 280 Electrical shutdown !!!!!!

[lowertrestrayle]

Any help please MB have no idea.
My V Class 280 ammbiente 1998 with only 38000 miles full MB history servised every year sometimes having only done 2000miles.
The Problem,
For no reason the battery charge light comes on then over a period of 1 or 2 mins all the rest of the warning lights come on, radio and satnav go out, it gets stuck in gear and stops. the sympton now is a flat battery as all you hear is a click from the starter, this first happened a month ago in france, AA jump start instantly but 5 min latter same as above, 'Alternater' he says, recovered to a garage, 1250Euros and 4 days later car OK for the next 2 hours of motorway driving then exactly the same problem, AA recovered to different garage, jumped it and it ran for 2 hours on forecourt with everthing possible on. so left and returned home all ok for 3 weeks and at the end of a 300mile run the same happened. didnt call AA but waited an hour and just had enough to turn over and fire up, drove to MB and 4 days latter they say NO FAULT FOUND, I have found out though that this is the 3rd Alternator in 4000 miles albeit that is over 2.5 years. Please has anyone else had the same problem and advice would be very much appreciated.

 

[brandwooddixon]

Initially, as I was reading this, I thought classic alternator problem. Then I read that you've had it changed 3 times and the problem still appears.

The slow "failure" of all those systems strikes me as being more likely due to undervoltage. Especially as the battery charge light comes on first.

Could this be the belt slipping on the alternator? Warped/loose plates in the battery? Certainly with so little mileage the battery is suspect, especially if left connected to the vehicle.

 

[lowertrestrayle]

Hi brandwooddixon, I was trying to be a accurate as possible, its a new battery aswell and the last time the charge light came on last, all the error codes are for under voltage.

 

[hmang]

did the new alternators come with new pulleys ?

or has the old one been refitted over & over?

 

[Hibbo]

Do these engines have a daft 'free-wheel' clutch type thing as part of their pully drive?

 

[dava]

Check your EARTH connections not live EARTHS. The ones to the engine and where it connects to the chassis. If it happens again, put a jump lead from the engine, good clean metal part and connect it direct to the goood clean earth connection on the battery, this eliminates the earths to the engine chassis etc. If it starts, then find and remove and clean all the earths. Take special attention to any braided earth wires, the belt type, ie braided bare flat earth straps, these corrode internally and allthough look good are full of green crude inside and give a bad resistance.

While your on check the bat connections to ensure good clean connections, any signs of green crud cut off and replace, vehicles that stand for long periods are prone to these sort of corrosion in the connections.

Also check the harness that feeds to the alty, akward to get to, for corroded connections, pull them apart inspect spray with wd40 and replace, this harness goes right back to the starter so check it out. Check the starter connections, also for corrosion and any wiring harness that is clipped to the engine, as these wear through and cause shorts giving allsorts of weird faults, you should be following the harness from the bat/alty/ starter and looking for metal clips holding it to the block/chassis etc.

If all of this shows no signs get back and I'll contact MB tech for you.
Hope it helps
Kind regards
Ray

 

[lowertrestrayle]

did the new alternators come with new pulleys ?

or has the old one been refitted over & over?

Hi the alternator came with a new pulley

 

[lowertrestrayle]

Check your EARTH connections not live EARTHS. The ones to the engine and where it connects to the chassis. If it happens again, put a jump lead from the engine, good clean metal part and connect it direct to the goood clean earth connection on the battery, this eliminates the earths to the engine chassis etc. If it starts, then find and remove and clean all the earths. Take special attention to any braided earth wires, the belt type, ie braided bare flat earth straps, these corrode internally and allthough look good are full of green crude inside and give a bad resistance.

While your on check the bat connections to ensure good clean connections, any signs of green crud cut off and replace, vehicles that stand for long periods are prone to these sort of corrosion in the connections.

Also check the harness that feeds to the alty, akward to get to, for corroded connections, pull them apart inspect spray with wd40 and replace, this harness goes right back to the starter so check it out. Check the starter connections, also for corrosion and any wiring harness that is clipped to the engine, as these wear through and cause shorts giving allsorts of weird faults, you should be following the harness from the bat/alty/ starter and looking for metal clips holding it to the block/chassis etc.

If all of this shows no signs get back and I'll contact MB tech for you.
Hope it helps
Kind regards
Ray

Hi Ray, Apparrently MB have exhausted all the checks you discripe and all checks out OK they wanted to use the vehicle as a run around so it could happen again but that could be a month or two or never!! there is no logic it could be in the middle of the day with nothing on or as has happened in the pitch black on a desserted road.
regards steve

 

[dava]

Just spoke to MB about it and they say 'possible ECU' sorry, mega bucks. But like you say it could be any thing realy need more info and time, might be worth letting them play with it.
Regards
Ray

 

[brandwooddixon]

I was going to suggest checking engine earthing straps etc, but Ray beat me to it.

With battery and alternator are working correctly then surely an undervoltage could only occur if there was a short or partial open circuit somewhere.

Would an ECU of some sort cause this? I don't know much about this model, but I'm not too sure about that.

The problem is either mechanical or electrical. Let me explain.

If electrical I'd be inclined to think that there is an intermittent short somewhere, causing the voltage to drop. If the short is bad enough then the alternator will eventually trip out in order to protect itself. The battery will then quickly drain as it wont be charged by the alternator.

You haven't mentioned any fuses being blown so we must assume that the short is somewhere between the battery and the alternator, rather than the battery and any ancilleries. As it happens unpredictably I'd suspect that there is either a frayed lead between the alternator and the battery, which moves under vibration and shorts out - look for possible signs of melted insulation between the alternator and the battery. Also look for any loose objects which could short out the alternator or battery.

If mechanical: Does your engine have a seprate drive belt for the alternator and ancilleries to the cam? Could this be slipping perhaps? A faulty belt tensioner? If for some reason the alternator isn't able to supply the amperage requried then the voltage would drop across the ancillerie devices.

 

[television]

This fault is nothing to do with under voltage. This is also the 3rd car this year with the same problem, to my knowledge the other have not been fixed or the owners never posted back.

I want a few hours thinking on it, the one thing in common with the others was the ignition switch going open circuit,they were cars that used the same switch, and mine failed. The car starts on the battery,it runs from the alternator, the switch is where everything meets, if you turn the ign off when driving along,all of the dash lights come on.

You can forget ECUs and the like, big problem for me is that I have no info for the V class, so what type of ignition switch is it on this car.

 

[dava]

Been busy today so have not had much time to get my head around it, so it's lunch time and I'll put a bit more to it.

Check your fuses, look mfor burnt melted ones, as some times the load is great and wont blow the fuse but due to the resistance heat and melt. Also look at relays, getting hot, pull themout and check for burnt/hot terminals, check the live feed to the fuse box and the back of this for corrosion or bunt connections.
Right back to me sarnies

 

[television]

Been busy today so have not had much time to get my head around it, so it's lunch time and I'll put a bit more to it.

Check your fuses, look mfor burnt melted ones, as some times the load is great and wont blow the fuse but due to the resistance heat and melt. Also look at relays, getting hot, pull themout and check for burnt/hot terminals, check the live feed to the fuse box and the back of this for corrosion or bunt connections.
Right back to me sarnies

Actually there are not any common fuses for this fault, please excuse me saying it

 

[lowertrestrayle]

This fault is nothing to do with under voltage. This is also the 3rd car this year with the same problem, to my knowledge the other have not been fixed or the owners never posted back.

I want a few hours thinking on it, the one thing in common with the others was the ignition switch going open circuit,they were cars that used the same switch, and mine failed. The car starts on the battery,it runs from the alternator, the switch is where everything meets, if you turn the ign off when driving along,all of the dash lights come on.

You can forget ECUs and the like, big problem for me is that I have no info for the V class, so what type of ignition switch is it on this car.

Thats interesting, it would be good to track them down, weres westcountry by the sea?

 

[dava]

Actually there are not any common fuses for this fault, please excuse me saying it

No probs mate, there just general things to check. We had one in this week that was going flat overnight, drawing 10 amps, keys out. Traced it to a faulty relay that was ingnition fed but had burnt and gone across the live feed, normally this would blow the fuse but it had just melted the holder. So there you go, elecs is always a nightmare, mech stuff you can see/hear the fault.
Ray

 

[television]

No probs mate, there just general things to check. We had one in this week that was going flat overnight, drawing 10 amps, keys out. Traced it to a faulty relay that was ingnition fed but had burnt and gone across the live feed, normally this would blow the fuse but it had just melted the holder. So there you go, elecs is always a nightmare, mech stuff you can see/hear the fault.
Ray

I agree with you, its not easy, It will be easier next year when we go back to starting handles and magnetos or spark box, maybe acetylene headlamps as well, keep up the good work

 

[lowertrestrayle]

many thanks guys it might always be a mystery, bought a portable power booster so I can start myself next time. just need to sort a few alternator warranty issues out with MB now cheers to all,

 

[fem]

I just ended upwith the same problem, can anyone advise of final remedy?

 

[BlackC55]

I would be looking at chaffed loom causing the alternator to short out. Difficult to find but not impossible.

Have a look behind the airbox. I have repaired the loom there before on a v-class.